St John, Maggie Jo
Prentice Hall ELT, 1994
Buku Teks
Berita Buana, 1977
Buku Teks
Wells, William D., author
Prentice-Hall, 2000
Buku Teks
Zyman, Sergio, author
John Wiley & Sons, 2002
Buku Teks
Moriarty, Sandra E. (Sandra Ernst), author
Pearson, 2012
Buku Teks